Behaviour, Ecology and Evolution (BEE) Laboratory, University of Sydney, Macleay Building A12, NSW 2006, Australia.
Wissenschaftskolleg zu Berlin, Wallotstrasse 19, 14193 Berlin, Germany.
Proc Biol Sci. 2021 Jun 9;288(1952):20210729. doi: 10.1098/rspb.2021.0729.
The ability to clone oneself has clear benefits-no need for mate hunting or dilution of one's genome in offspring. It is therefore unsurprising that some populations of haplo-diploid social insects have evolved thelytokous parthenogenesis-the virgin birth of a female. But thelytokous parthenogenesis has a downside: the loss of heterozygosity (LoH) as a consequence of genetic recombination. LoH in haplo-diploid insects can be highly deleterious because female sex determination often relies on heterozygosity at sex-determining loci. The two female castes of the Cape honeybee, , differ in their mode of reproduction. While workers always reproduce thelytokously, queens always mate and reproduce sexually. For workers, it is important to reduce the frequency of recombination so as to not produce offspring that are homozygous. Here, we ask whether recombination rates differ between Cape workers and Cape queens that we experimentally manipulated to reproduce thelytokously. We tested our hypothesis that Cape workers have evolved mechanisms that restrain genetic recombination, whereas queens have no need for such mechanisms because they reproduce sexually. Using a combination of microsatellite genotyping and whole-genome sequencing we find that a reduction in recombination is confined to workers only.
克隆自己的能力有明显的好处——不需要配偶狩猎或后代基因组的稀释。因此,一些单倍二倍体社会昆虫种群进化出了孤雌生殖——雌性的处女生育。但是孤雌生殖有一个缺点:遗传重组导致杂合性丢失(LoH)。单倍二倍体昆虫中的 LoH 可能是非常有害的,因为雌性性别决定通常依赖于性别决定基因座的杂合性。海角蜜蜂的两种雌性蜂型, ,在繁殖方式上有所不同。虽然工蜂总是孤雌生殖,但蜂王总是交配并进行有性生殖。对于工蜂来说,减少重组的频率以避免产生纯合后代非常重要。在这里,我们询问是否可以通过实验操纵来重现孤雌生殖,从而改变海角工蜂和海角蜂王的重组率。我们假设海角工蜂已经进化出了限制遗传重组的机制,而蜂王则不需要这种机制,因为它们进行有性生殖。我们使用微卫星基因分型和全基因组测序的组合,发现重组减少仅局限于工蜂。